multi resolution needed in order to sculpt?
You can sculpt a simple mesh (a cube) without anything else.

You can sculpt any mesh and use dyntopo. You'll get a full triangulated mesh with as much topo as you want/can, exactly where you need it.

You can sculpt on a quad based mesh with multires. You'll get a new level of details with each subdiv. The whole mesh is subdivided.

But using a multires on dyntopo is exactly what you shouldn't do. Multires (or subdivision) is not supposed to work well with triangles.

Both have pros and cons, they are a different way to do sculpting.

a Cube with quad and a cube with triangulated faces, with a subdivision (same as multires):